I'm pretty sure from all the other Curation Reward articles I've read, that the first 30 minutes is a (linear) sliding % from
- (0 minutes after post )100% author - 0% curator
- (15 minutes after post) 50% author - 50% curator
- (30+ minutes after post) 0% author - 100% curator
Also, that the Curation Reward is only 25% of the net article value now. It used to be 50% of it. Then it is split up by a formula of who has upvoted first with more Steam Power than others. So if a post gets upvoted with "Big Steam Power" after your upvote, that helps you way more than if "Big Steam Power" upvotes before you.
TIPS: Read through several of these articles until you get an idea of the model. Be aware of the model change from 50/50 author/curation to 75/25 author/curation. Also if you're a visual person, look for an article or two with graphs.